KUSA - Participants never know what might come their way with Oyster The Race, however whatever the challenge, they know it's going to be fun.

The original urban adventure race that sends teams of three to six throughout the city on a mystery course on foot and bike, returns to its home of Denver August 24. Featuring 10-30 mile courses, combining athleticism and intelligence, where participants run, bike, perform bizarre tasks, and solve mind bending puzzles.

"Denver is home to the Oyster; it began here in 2003 and was originally dubbed a 'Rocky Mountain ball buster,' taken from the novelty dish Rocky Mountain Oysters," says Jason Ornstein, executive director of adventure for the Oyster Racing Series and Team Player Productions. "Now simply named 'Oyster The Race,' it has become best known for the fun and unique way it challenges both minds and bodies."

The race unfolds one leg at a time. Participants take off at the starting area and are given a passport explaining the task at hand and instructions. Once a passport is completed the next one is handed out. Although the exact course is a tightly guarded secret until race day, past legs have included scavenger hunts around the city, devouring mystery food, beer pong and more, in addition to running, biking, paddling, and climbing. One past leg, Take Me Out To The Ball Game, had racers make their way to Coors Field on foot. Teams then were tied together before searching for puzzle pieces in designated sections and putting them together to reveal the next checkpoint.

The Denver Oyster will again benefit Make-A-Wish Colorado this year, which grants the wishes of children with life-threatening medical conditions.